The present invention relates to an image forming apparatus such as a printer, a copying machine or a facsimile machine, and in particular, to a cooling technology in the apparatus.
In an image forming apparatus employing an imagewise exposure device whose light source is a laser, there is provided a cooling device on the exposure device because heat generated on a polygon motor or the like makes a temperature of the exposure device to rise.
In the image forming apparatus, heat generating sources such as a fixing unit and others are provided in addition to the polygon motor, and a cooling device is provided for controlling a temperature rise that is caused by heat generated by the aforesaid items.
In Japanese TOKKAI No. 2000-261174, for example, a flow path for cooling air is formed between a fixing unit and a laser-writing unit that is arranged above the fixing unit, so that a rise in temperature of the laser-writing unit caused by heat coming from the fixing unit may be prevented, and a rise in temperature caused by heat generated on the laser-writing unit may be prevented.
In Japanese TOKKAIHEI No. 11-212674, there is described a cooling method of an information processing apparatus of a rack-cabinet-housed type wherein a rack-cabinet is composed of a plurality of stays, and a part of the stays are used as a means to introduce cooling air and the others are used as a means to exhaust air.
In the cooling technology disclosed by Japanese TOKKAI No. 2000-261174, the cooling means scarcely contribute to reinforcement of a main body frame of an image forming apparatus. For this reason, the main body frame has been designed, in terms of materials and thickness, to be capable of satisfying necessary conditions for the strength of the apparatus, resulting in problems of high cost and an increase of mass. Thus, there has been a problem that a considerable increase in cost cannot be avoided, because an increase in cost for providing a cooling device is added to the aforementioned high cost.
In Japanese TOKKAIHEI No. 11-212674, there is provided an organization to cool the whole of an apparatus such as a server apparatus, and there is a problem that it is difficult to obtain a cooling function necessary to cool a specific portion in the apparatus, in the same way as in the image forming apparatus.
Further, in the case of the image forming apparatus, there is introduced a business style in which the same manufacturer places plural types of apparatus on the market simultaneously. In this business style, parts are made to be uniform among the plural types of equipment, to achieve rationalization such as cost reduction.
In the image forming apparatus, there are housed many units such as an exposure device, a developing unit and a cleaning unit which require cooling, and the number, types and installation positions for these units vary depending on the types of equipment, and therefore, the cooling means are different each other depending on the types of equipment, which results in a problem that uniformalization of parts is not advanced.